Exemplary embodiments of this invention generally relate to pressure relief valves and, more particularly, to a pressure relief valve configured to prevent damage to a fan.
An air cycle environmental control system (ECS) may be used to regulate the conditions of an enclosed environment, such as an aircraft cabin for example. An ECS generally includes a compress for pressurizing air input thereto, and a turbine for driving the compressor and for expanding and cooling the air. The ECS may be powered by the air input thereto from a compressor section of an engine, or may be powered by an auxiliary power unit (APU).
Check valves or other relief valves are commonly used in the air management circuits of the ECS to provide a bypass flow path when a ram system of the ECS is not functioning properly. Air drawn into a ram system by a fan first passes through a filter configured to prevent debris and particles from circulating through the ECS. Over time, the particles collected within the filter may form a blockage in the filter, thereby limiting the air drawn through the filter by the fan. The lack of air flowing through the filter may cause the fan to stall or operate in a surge condition which may lead to damage, or ultimately, replacement of the fan.